Warning
The amber maintenance/warning indicator is used for recommended service or machine warnings. The manual notes that the compressor will often continue to operate, but the condition should be resolved promptly so it does not progress to a fault or damage.
Fault
The red fault indicator means a compressor fault has occurred. The controller keeps the compressor inoperative until the fault condition is corrected.
Practical rule
Record the exact message, operating mode and key readings before clearing a message. A reset can remove a useful clue even when it does not fix the cause.
Source
Based on Sullair STS Controller User Manual, part 02250241-178 R01, referenced pages 8, 19.